1. Field of the Invention
The present invention relates to a method and the inspection equipment for inspecting defects of wafer suited for detecting a COP defect in a regular octahedral form surrounded by {111} crystal planes of grown-in defects, crystal defects in single crystal of silicon.
2. Description of the Related Art
For fine defects existing in a silicon single crystal produced by the Czochralski method (CZ method), a COP (Crystal Originated Particle) defect has been detected. The existence of the COP defect has been confirmed by detecting a pit formed in the silicon wafer by washing using the SC-1 liquid effective for removal of particles on the silicon wafer. However, since the size of the pit of the COP defect ranges from around 0.1 to 0.2 .mu.m and the density of the COP defect in the crystal is as low as 1.times.10.sup.5 to 1 .times.10.sup.7 (cm.sup.-3), there are few cases in which the defect was directly observed. However, the form of COP in the silicon single crystal has been confirmed to be a microscopic regular octahedron surrounded with the {111} crystal planes.
The pit of the COP defect formed on the silicon wafer surface in this way has a fear of deteriorating pressure-resistance characteristics of the oxide film formed on the silicon wafer. In recent years, in the MOS device, as the number of bits increases, refinement and increased area of the chip have been promoted, and severity of the requirements for characteristics of gate oxide film further increases. Therefore, studies on Grown-in defects, crystal defects such as COP defects, etc., have been actively carried forward. Consequently, in order to study the COP defects, it is essential to detect defects such as the COP defects, etc with cerainty.